1. Field of the Invention
The present invention relates to an alternating current generator having neither a rotating field nor a rotating armature. The rotating element, or rotor, is comprised of a number of core sections common to the cores of both exciter field and armature. The rotor has no rotating poles and there are no rotating coils.
2. General Background
Rotating electromagnetic alternating current generators depend for their production of electricity on the principal that a coil of conducting wire will have a current induced in its windings when the coil is subjected to a varying magnetic field, and that magnetic substances, such as iron, are capable of concentrating the magnetic flux surrounding the coil. By rotating coils in magnetic fields, or by rotating magnets in proximity to coils, the consequent variance of magnetism relative to the coils can be obtained.
Most alternating current (AC) generators now used for the production and transmission of electrical power for general use have a constant frequency (the rotor turns at a controlled rotational velocity) and a constant output voltage. They are of the type that utilizes a rotating magnetic field, produced by a regulated current through rotating coils to induce the desired current in a group of armature coils. Electromagnets are arranged on a rotor so that the poles facing the cores of the armature are alternately north and south. When the rotor is turned, the poles pass the armature cores, reversing the magnetic flux presented to them with the passing of each north-south pair, and so inducing an alternating electric current in the armature coils. The windings of the rotating exciter are led to a pair of slip rings, allowing a regulated current to enter and exit by means of brush contact with the slip rings. The amount of current through the rotating coils determines the strength of the exciter magnets, which in turn determines the voltage amplitude of the output.
Production of electrical power where neither voltage nor frequency control is important can usually be accomplished economically by a magneto, which uses permanent magnets about the rotor instead of electromagnets. The current is induced in the same manner as above, but the field strength of the permanent magnets is constant so that the voltage control has to be accomplished by varying the output resistance of the load. Its primary use is as a generator of ignition sparks, or for charging batteries after rectification to direct current.
When the output requires a controlled voltage but frequency is not important, another type of generator, similar to a magneto, is used. This type also induces current in an armature by passing alternate magnetic poles in proximity to magnetic cores, but the poles are aligned with the axle, and staggered so as to change the magnetic path through the armature cores. The rotating field magnet has a section concentric with the shaft that turns within a fixed coil so that no brushes are needed. Means of supporting this inner fixed coil presents a problem for resolution of which a multitude of designs have been proposed. Commonly known as an alternator, this type of generator is mainly used on vehicles, where it charges storage batteries after being rectified to direct current.
Several devices relating to alternating current generators have been patented.
U.S. Pat. No. 3,418,506, by Parker, discloses an axial airgap generator having a plurality of rotor and stator sections spaced from one another and mounted on a central shaft, wherein at least one of the stator sections carries windings for generating a magnetomotive force, and the rotors are surrounded by electrical conductors such as coil windings leading to slip rings.
U.S. Pat. No. 4,506,180, by Shizuka, et al., discloses a fixed field inductor-type generator wherein a fixed coil is mounted around a pair of pawl-like magnetic poles mounted on a rotary shaft.
U.S. Pat. No. 5,864,198, by Pinkerton, discloses a brushless generator wherein rotating coils pass through stationary electromagnetic fields to induce AC current in the coils, which is in turn used by a set of rotating electromagnets to induce an AC voltage in a second set of coils.
Other devices disclosed in U.S. Pat. Nos. 3,569,804; 3,571,639; 3,610,979; 4,041,340; 4,075,519; and 4,611,139 are representative of the state of the art, however an alternating current generator has not been previously proposed wherein the rotor has no rotating coils and no rotating poles.
It is an object of the present invention to provide an electromagnetic alternating current generator having neither a rotating field nor a rotating armature, comprised of a shaft mounted non-magnetic disc with blocks made of a suitable magnetic material having low permeability fastened to its rim, and two stationary cores, the first being electromagnetic exciter core, and the second being an armature capable of being magnetized. When the rotor is caused to rotate by a driver engine, the blocks pass in close proximity to the poles of the stationary cores. As the blocks reach a first position, they complete a magnetic circuit between the electromagnet of the exciter core and the armature, thereby producing magnetic flux in the armature core. As the blocks reach a second position, the circuit is broken, dropping the magnetic flux in the armature to zero, which induces a current in a solenoid type wire wound around a section of the core. When the blocks reach a third position, they again complete a magnetic circuit, but with opposite poles of the electromagnet. This reverses the magnetic flux in the armature core, again inducing a current, but with opposite polarity, thus generating alternating current.